Release in radial growth in the trunk and structural roots of white spruce as measured by dendrochronology

We used a new technique to examine the response of the trunk and structural roots of white spruce (Piceaglauca (Moench) Voss) to an increase in wind exposure. Ring widths were measured in the roots and trunks of trees located within a 120-year-old, boreal mixedwood stand (control) and at the edge of a road built through the stand 16 years before sampling (released). The observed ring widths were divided by widths predicted from regression to produce ring indices. Response indices were produced by subtracting the ring indices of control trees from those of released trees. Allocation indices were produced by subtracting the ring indices of trunks from those of roots. A final index, quantifying the change in allocation to the root and trunk after road clearing, was produced by subtracting allocation indices of control trees from those of released trees. Following the road clearing, the rate of trunk diameter growth remained unchanged for 3–9 years, while root diameter growth increased. These observations sug...